Method of forming a magnetic tunnel junction device

ABSTRACT

A method of forming a magnetic tunnel junction device is disclosed that includes forming a trench in a substrate, the trench including a plurality of sidewalls and a bottom wall. The method includes depositing a first conductive material within the trench proximate to one of the sidewalls and depositing a second conductive material within the trench. The method further includes depositing a material to form a magnetic tunnel junction (MTJ) structure within the trench. The MTJ structure includes a fixed magnetic layer having a magnetic field with a fixed magnetic orientation, a tunnel junction layer, and a free magnetic layer having a magnetic field with a configurable magnetic orientation. The method further includes selectively removing a portion of the MTJ structure to create an opening in the MTJ structure.

I. CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority from and is a divisionalapplication of U.S. patent application Ser. No. 13/663,806, filed Oct.30, 2012, which claims priority from and is a continuation applicationof U.S. patent application Ser. No. 12/780,174, filed May 14, 2010, (nowU.S. Pat. No. 8,680,592), which claims priority from and is acontinuation application of U.S. patent application Ser. No. 12/044,596,filed Mar. 7, 2008, (now U.S. Pat. No. 7,781,231), the content of eachof which is incorporated by reference herein in its entirety.

II. FIELD

The present disclosure is generally related to a method of forming amagnetic tunnel junction device.

III. DESCRIPTION OF RELATED ART

In general, widespread adoption of portable computing devices andwireless communication devices has increased demand for high-density andlow-power non-volatile memory. As process technologies have improved, ithas become possible to fabricate magneto-resistive random access memory(MRAM) based on magnetic tunnel junction (MTJ) devices. Traditional spintorque tunnel (STT) junction devices are typically formed as flat stackstructures. Such devices typically have two-dimensional magnetic tunneljunction (MTJ) cells with a single magnetic domain. An MTJ celltypically includes an anti-ferromagnetic layer (AF), a fixed magneticlayer, a barrier layer (i.e., a tunneling oxide layer), and a freemagnetic layer, where a bit value is represented by a magnetic fieldinduced in the free magnetic layer. A direction of the magnetic field ofthe free layer relative to a direction of a fixed magnetic field carriedby the fixed magnetic layer determines the bit value.

Conventionally, to improve data density using MTJ devices, one techniqueincludes reducing the size of MTJ devices to put more MTJ devices in asmaller area However, the size of the MTJ devices is limited by thefabrication process technology. Another technique involves formingmultiple MTJ structures in a single MTJ device. For example, in oneinstance, a first MTJ structure is formed that includes a first fixedlayer, a first tunnel barrier, and a first free layer. A dielectricmaterial layer is formed on the first MTJ structure, and a second MTJstructure is formed on top of the dielectric material layer. Suchstructures increase the density of storage in an X-Y direction whileincreasing a size of the memory array in a z-direction. Unfortunately,such structures store only one bit per cell, so the data density in theX-Y direction is increased at the expense of area in a Z-direction andcost of manufacture. Further, such structures increase wire-tracerouting complexity. Hence, there is a need for improved memory deviceswith greater storage density without increasing a circuit area of eachof the MTJ cells and that can scale with the process technology.

IV. SUMMARY

In a particular embodiment, a magnetic tunnel junction (MTJ) deviceincludes a substrate having a trench. The MTJ device further includes aconductive terminal disposed within the trench. The conductive terminalincludes a first conductive terminal disposed within the trench, wherethe first conductive terminal forms a first electrode, and a secondconductive terminal disposed within the trench, where the secondconductive terminal forms a second electrode. The MTJ device furtherincludes a magnetic tunnel junction (MTJ) structure disposed within thetrench. The MTJ structure includes a fixed magnetic layer having a fixedmagnetic orientation, a tunnel junction layer, and a free magnetic layerhaving a configurable magnetic orientation. The fixed magnetic layer iscoupled to the conductive terminal along an interface that extendssubstantially normal to a surface of the substrate. The free magneticlayer is proximate to the conductive terminal and is configured to carrya magnetic domain configured to represent a digital value.

In another particular embodiment, a method of forming a magnetic tunneljunction device is disclosed that includes forming a trench in asubstrate, the trench including a first sidewall, a second sidewall, athird sidewall, a fourth sidewall, and a bottom wall. The methodincludes depositing a first conductive material within the trenchproximate to the first sidewall and depositing a second conductivematerial within the trench. The method further includes depositing amagnetic tunnel junction (MTJ) structure within the trench. The MTJstructure includes a fixed magnetic layer having a magnetic field with afixed magnetic orientation, a tunnel junction layer, and a free magneticlayer having a magnetic field with a configurable magnetic orientation.The MTJ structure is adjacent to the first, the second, the third, andthe fourth sidewalls at respective first, second, third, and fourthlateral interfaces and adjacent to the bottom wall at a bottominterface. The method further includes selectively removing a portion ofthe MTJ structure that is adjacent to the fourth sidewall to create anopening such that the MTJ structure is substantially u-shaped.

In still another particular embodiment, a magnetic tunnel junction (MTJ)device includes a substrate including a trench having a first sidewalland a second sidewall. A first electrode is disposed within the trenchadjacent to the first sidewall, and a second electrode is disposedwithin the trench adjacent to the second sidewall. The MTJ devicefurther includes a magnetic tunnel junction (MTJ) structure disposedwithin the trench. The MTJ structure includes a fixed magnetic layerhaving a magnetic field with a fixed magnetic orientation, a tunneljunction layer, and a free magnetic layer having a magnetic field with aconfigurable magnetic orientation. The MTJ structure contacts the firstelectrode at a first interface and contacts the second electrode at asecond interface. The MTJ device further includes a bottom electrodedisposed within the trench adjacent to a bottom wall of the trench. Thefree magnetic layer includes a bottom portion adjacent to the bottomelectrode, where the bottom portion is configured to carry a magneticdomain to store a digital value.

One particular advantage of the magnetic tunnel junction (MTJ) device isthat multiple data bits may be stored at a single MTJ cell. In thisinstance, a data storage density of a single bit MTJ cell my beincreased (e.g., doubled, tripled or quadrupled), depending on theparticular implementation.

Still another particular advantage is that the MTJ cell can includemultiple independent magnetic domains to store multiple data bits. In aparticular embodiment, the MTJ cell can include multiple sidewalk(extending from a planar surface of a substrate), where each of themultiple sidewalls carries a unique magnetic domain to represent astored data bit value. Additionally, the MTJ cell can include a bottomwall including a horizontal magnetic domain to represent another databit value.

Yet another particular advantage is provided in that the MTJ cell caninclude multiple independent magnetic domains. Each of the multipleindependent magnetic domains may be written to or read from withoutchanging other magnetic domains within the MTJ cell.

Other aspects, advantages, and features of the present disclosure willbecome apparent after review of the entire application, including thefollowing sections: Brief Description of the Drawings, DetailedDescription, and the Claims.

V. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional diagram of a particular illustrativeembodiment of a magnetic tunnel junction (MTJ) stack including lateralmagnetic domains;

FIG. 2 is top view of a particular illustrative embodiment of a circuitdevice including an MTJ cell having multiple lateral magnetic domains;

FIG. 3 is a cross-sectional diagram of the circuit device of FIG. 2taken along line 3-3 in FIG. 2;

FIG. 4 is a cross-sectional diagram of the circuit device of FIG. 2taken along line 4-4 in FIG. 2;

FIG. 5 is top view of a second particular illustrative embodiment of acircuit device including an MTJ cell having multiple lateral magneticdomains;

FIG. 6 is a cross-sectional diagram of the circuit device of FIG. 5taken along line 6-6 in FIG. 5;

FIG. 7 is a cross-sectional diagram of the circuit device of FIG. 5taken along line 7-7 in FIG. 5;

FIG. 8 is top view of a third particular illustrative embodiment of acircuit device including an MTJ cell having multiple lateral magneticdomains;

FIG. 9 is a cross-sectional diagram of the circuit device of FIG. 8taken along line 9-9 in FIG. 8;

FIG. 10 is a cross-sectional diagram of the circuit device of FIG. 8taken along line 10-10 in FIG. 8;

FIG. 11 is top view of a fourth particular illustrative embodiment of acircuit device including an MTJ cell having multiple lateral magneticdomains;

FIG. 12 is a cross-sectional diagram of the circuit device of FIG. 11taken along line 12-12 in FIG. 11;

FIG. 13 is a cross-sectional diagram of the circuit device of FIG. 11taken along line 13-13 in FIG. 11;

FIG. 14 is top view of a fifth particular illustrative embodiment of acircuit device including an MTJ cell having multiple lateral magneticdomains;

FIG. 15 is a cross-sectional diagram of the circuit device of FIG. 14taken along line 15-15 in FIG. 14;

FIG. 16 is a cross-sectional diagram of the circuit device of FIG. 14taken along line 16-16 in FIG. 14;

FIG. 17 is top view of a sixth particular illustrative embodiment of acircuit device including an MTJ cell having multiple lateral magneticdomains;

FIG. 18 is a cross-sectional diagram of the circuit device of FIG. 17taken along line 18-18 in FIG. 17;

FIG. 19 is a cross-sectional diagram of the circuit device of FIG. 17taken along line 19-19 in FIG. 17;

FIG. 20 is top view of a seventh particular illustrative embodiment of acircuit device including an MTJ cell having multiple lateral magneticdomains;

FIG. 21 is a cross-sectional diagram of the circuit device of FIG. 20taken along line 21-21 in FIG. 20;

FIG. 22 is a cross-sectional diagram of the circuit device of FIG. 20taken along line 22-22 in FIG. 20;

FIG. 23 is top view of a eighth particular illustrative embodiment of acircuit device including an MTJ cell having multiple lateral magneticdomains;

FIG. 24 is a cross-sectional diagram of the circuit device of FIG. 23taken along line 24-24 in FIG. 23;

FIG. 25 is a cross-sectional diagram of the circuit device of FIG. 23taken along line 25-25 in FIG. 23;

FIG. 26 is a top view of a free layer of an MTJ cell having multiplelateral magnetic domains configured in a zero-value state;

FIG. 27 is a cross-sectional view of an MTJ cell including the freelayer of FIG. 26 illustrating a write current to configure the magneticdomains of the free layer to represent a zero value;

FIG. 28 is cross-sectional view of the free layer of FIG. 26 taken alongline 28-28 in FIG. 26;

FIG. 29 is a cross-sectional view of the free layer of FIG. 26 takenalong line 29-29 in FIG. 26;

FIG. 30 is a top view of a five layer of an having multiple lateralmagnetic domains configured in a one-value state;

FIG. 31 is a cross-sectional view of an MTJ cell including the freelayer of FIG. 30 illustrating a write current to configure the magneticdomains of the free layer to represent a one value;

FIG. 32 is cross-sectional view of the free layer of FIG. 30 taken alongline 32-32 in FIG. 30;

FIG. 33 is a cross-sectional view of the free layer of FIG. 30 takenalong line 33-33 in FIG. 30;

FIG. 34 is a cross-sectional view of a particular embodiment of a MTJcell;

FIG. 35 is a cross-sectional view of another particular embodiment of anMTJ cell that provides an increased resistance;

FIG. 36 is a cross-sectional view of an MTJ cell having a single switchdevice to access a single stored value;

FIG. 37 is a cross-sectional diagram of an MTJ cell having two switchdevices to access two stored values;

FIG. 38 is a cross-sectional diagram of an MTJ cell a three switchdevices to access three stored values;

FIGS. 39-40 are flow diagrams of a particular illustrative embodiment ofa method of forming a magnetic tunnel junction (MTJ) structure havingmultiple lateral magnetic domains;

FIG. 41 is a flow diagram of a second particular illustrative embodimentof a method of forming a magnetic tunnel junction (MTJ) structure havingmultiple lateral magnetic domains;

FIG. 42 is a flow diagram of a third particular illustrative embodimentof a method of forming a magnetic tunnel junction (MTJ) structure havingmultiple lateral magnetic domains; and

FIG. 43 is a block diagram of a wireless communication device includingmemory circuits comprises of MTJ cells.

VI. DETAILED DESCRIPTION

FIG. 1 is a cross-sectional diagram of a particular illustrativeembodiment of a magnetic tunnel junction (MTJ) cell 100 includinglateral magnetic domains. The MTJ cell 100 includes a magnetic tunneljunction (MTJ) structure 104 having an MTJ stack 106, a center electrode108, a first lateral electrode 110, and a second lateral electrode 112.The MTJ stack 106 includes a fixed magnetic layer 114 that carries amagnetic domain having a fixed magnetic orientation, a tunnel barrierlayer 116, and a free magnetic layer 118 having a configurable magneticorientation. The MTJ stack 106 may also include an anti-ferromagnetic(AF) layer (not shown) that pins the fixed magnetic layer 114. The MTJstack 106 may also include additional layers (not shown). The fixedmagnetic layer 114 is coupled to the first lateral electrode 110 via theAF layer at first lateral interface 120 and contacts the second lateralelectrode 112 at a second lateral interface 122. It should be understoodthat the fixed magnetic layer 114 and the five magnetic layer 118 may beswitched, such that the free magnetic layer 118 contacts the first andsecond lateral electrodes 110 and 112 at the first and second lateralinterfaces 120 and 122, respectively. In general, the free magneticlayer 118 has a first portion that carries a first magnetic domain 124(illustrated at 2612 in FIG. 26) adjacent to the first lateral electrode110 and has a second portion that carries a second magnetic domain 126(illustrated at 2616 in FIG. 26) adjacent to the second lateralelectrode 1

In a particular embodiment, the dimensions of the MTJ cell 100 (i.e.,length, width, and depth) determine an orientation of a magnetic domainwithin the free layer 118. In particular, the magnetic domain along aparticular wall aligns in a direction corresponding to a longestdimension of the particular wall. If the wall has a depth that isgreater than its length, the magnetic domain is oriented in a directionof the depth. In contrast, if the wall has a length that is greater thanthe depth, the magnetic domain is oriented in a direction of the length.The particular direction of the magnetic field associated with themagnetic domain of the free layer 118 relative to a fixed direction of amagnetic field associated with the magnetic domain of the fixed layer114 represents a data hit value.

In another particular embodiment, the fixed magnetic layer 114 and thefree magnetic layer 118 are formed from a ferromagnetic material. Thetunnel barrier layer 116 may be formed from oxidation of metal material,such as magnesium oxide (MgO). A read current may be applied via thecenter electrode 108 and the lateral electrodes 110 and 112 to read databit values represented by the first magnetic domain 124 and the secondmagnetic domain 126. In a particular example, the first magnetic domain124 and the second magnetic domain 126 may be adapted to representunique data bit values.

FIG. 2 is top view of a particular illustrative embodiment of a circuitdevice 200 including an MTJ cell having multiple lateral magneticdomains. The circuit device 200 includes a substrate 202. The substrate202 includes a magnetic tunnel junction (MTJ) structure 204 that has anMTJ stack 206, a center electrode 208, a first lateral electrode 210,and a second lateral electrode 212. The MTJ stack 206 has a length (a)and a width (b), where the length (a) is greater than the width (b). Thesubstrate 202 includes a first via 214 coupled to the first lateralelectrode 210, a center via 216 coupled to the center electrode 208, anda second via 218 coupled to the second lateral electrode 212. Thesubstrate 202 also includes a first wire trace 220 coupled to the firstvia 214, a second wire trace 222 coupled to the second via 218, and athird wire trace 224 coupled to the center via 216. The substrate 202also includes a process opening 226. In a particular embodiment, the MTJstructure 204 is adapted to store a first data value, such as a firstbit value, and a second data value, such as a second bit value, within afree layer of the MTJ stack 206 that is adjacent to the first and secondlateral electrodes 210 and 212.

FIG. 3 is a cross-sectional diagram 300 of the circuit device 200 ofFIG. 2 taken along line 3-3 in FIG. 2. The diagram 300 illustrates thesubstrate 202 including a first inter-layer dielectric layer 332, afirst cap layer 334, a second inter-layer dielectric layer 336, a secondcap layer 338, a third cap layer 340, a third inter-layer dielectriclayer 342, and a fourth inter-layer dielectric layer 344. The substrate202 includes a first surface 360 and a second surface 370. The substrate202 also includes the MTJ structure 204 including the MTJ stack 206. Thefirst lateral electrode 210, the second lateral electrode 212, and theMTJ stack 206 are disposed within a trench in the substrate 202. Thetrench has a depth (d). The substrate 202 includes the first, second andthird wire traces 220, 222, and 224 deposited and patterned at the firstsurface 360. The first wire trace 220 is coupled to the first via 214,which extends from the first wire trace 220 to the first lateralelectrode 210. The second wire trace 222 is coupled to the second via218, which extends from the second wire trace 222 to the second lateralelectrode 212. The third wire trace 224 is coupled to the center via216, which extends from the third wire trace 224 to the center (top)electrode 208. The center electrode 208 is coupled to the MTJ stack 206.

In general, the MTJ stack 206 is adapted to store a first data bit valuewithin a first portion of the free layer of the MTJ stack 206 that isadjacent to the first lateral electrode 210. The MTJ stack 206 is alsoadapted to store a second data bit value within a second portion of thefree layer of the MTJ stack 206 that is adjacent to the second lateralelectrode 212. A data bit value can be read from the MTJ stack 206 byapplying a voltage between the third wire trace 224 and the first wiretrace 220 or the second wire trace 222 and by comparing a current at thefirst wire trace 220 and/or the second wire trace 222 to a referencecurrent. Alternatively, a data bit value may be written to the MTJ stack206 by applying a write current between the first wire trace 220 and thethird wire trace 224 or between the second wire trace 222 and the thirdwire trace 224. In a particular embodiment, the width (b) of the MTJstack 206 illustrated in FIG. 2 is greater than the depth (d), andrespective magnetic domains carried by a free layer within the MTJ stack206 adjacent to the lateral electrodes 210 and 212, extend in adirection that is substantially parallel to the surface 360 of thesubstrate 202 in a direction of the width (b) of the MTJ stack 206(i.e., into or out from the page view of FIG. 3). If the width (b) ofthe MTJ stack 206 is less than the depth (d), respective magnetic fieldsof the free layer within the MTJ stack 206 adjacent to the lateralelectrodes 210 and 212 may be vertical, i.e. along the trench depthdirection. Generally, the MTJ structures illustrated in FIGS. 2-13 maybe patterned by reverse trench photo-etch processes and MTJChemical-Mechanical Polishing (CMP) processes to control trenchdimensions, and therefore to control the MTJ dimensions.

FIG. 4 is a cross-sectional diagram 400 of the circuit device 200 ofFIG. 2 taken along line 4-4 in FIG. 2. The diagram 400 includes thesubstrate 202 having the first inter-layer dielectric layer 332, thefirst cap layer 334, the second inter-layer dielectric layer 336, thesecond cap layer the third cap layer 340, the third inter-layerdielectric layer 342, and the fourth inter-layer dielectric layer 344.The substrate 202 includes the MTJ stack 206, the top electrode 208, anda center via 216 that extends from the third wire trace 224 to the topelectrode 208. The substrate 202, also includes the process opening 226,which may be formed by selectively removing a portion of the MTJstructure 204 and filled by depositing an inter-layer dielectricmaterial within the processing opening 226.

In a particular illustrative embodiment, the MTJ structure 204 is asubstantially u-shaped structure including three sidewalls and a bottomwall. The MTJ structure 204 can include lateral electrodes, such as thefirst and second lateral electrodes 210 and 212, that are associatedwith respective sidewalls and can include a bottom electrode that isassociated with the bottom wall. Additionally, the structure 204 isadapted to store up to four unique data bits.

FIG. 5 is top view of a particular illustrative embodiment of a circuitdevice 500 including an MTJ cell having multiple lateral magneticdomains. The circuit device 500 includes a substrate 502. The substrate502 includes a magnetic tunnel junction (MTJ) structure 504 that has anMTJ stack 506, a center electrode 508, a first lateral electrode 510,and a second lateral electrode 512. The MTJ stack 506 has a length (a)and a width (b). The substrate 502 includes a first via 514 coupled tothe first lateral electrode 510, a center via 516 coupled to the centerelectrode 508, and a second via 518 coupled to the second lateralelectrode 512. The substrate 502 also includes a first wire trace 520coupled to the first via 514, a second wire trace 522 coupled to thesecond via 518, and a third wire trace 524 coupled to the center via516. The substrate 502 also includes a process opening 526. In aparticular embodiment, the MTJ structure 504 is adapted to store a firstdata bit value and a second data bit value within a free layer of theMTJ stack 506 that is adjacent to the first and second lateralelectrodes 510 and 512.

FIG. 6 is a cross-sectional diagram 600 of the circuit device 500 ofFIG. 5 taken along line 6-6 in FIG. 5. The diagram 600 illustrates thesubstrate 502 including a first inter-layer dielectric layer 630, asecond inter-layer dielectric layer 632, a first cap layer 634, a thirdinter-layer dielectric layer 636, a second cap layer 638, a third caplayer 640, a fourth inter-layer dielectric layer 642, and a fifthinter-layer dielectric layer 644. The substrate 502 includes a firstsurface 660 and a second surface 670. The substrate 502 also includesthe MTJ structure 504 including the MTJ stack 506. The first lateralelectrode 510, the second lateral electrode 512, and the MTJ stack 506are disposed within a trench in the substrate 502. The trench has adepth (d). The substrate 502 includes the third wire trace 524 depositedand patterned at the first surface 660 and includes the first and secondwire traces 520 and 522 deposited and patterned at the second surface670. The first wire trace 520 is coupled to the first via 514, whichextends from the first wire trace 520 to the first lateral electrode510. The second wire trace 522 is coupled to the second via 518, whichextends from the second wire trace 522 to the second lateral electrode512. The third wire trace 524 is coupled to the center via 516, whichextends from the third wire trace 524 to the center (top) electrode 508.The center electrode 508 is coupled to the MTJ stack 506.

In general, the MTJ stack 506 is adapted to store a first data bit valuewithin a free layer of the MTJ stack 506 that is adjacent to the firstlateral electrode 510. The MTJ stack 506 is also adapted to store asecond data bit value within the free layer of the MTJ stack 506 that isadjacent to the second lateral electrode 512. A data bit value can beread from the MTJ stack 506 by applying a voltage between the third wiretrace 524 and the first wire trace 520 or the second wire trace 522 andby comparing a current at the first wire trace 520 and/or the secondwire trace 522 to a reference current. Alternatively, a data bit valuemay be written to the MTJ stack 506 by applying a write current betweenthe first wire trace 520 and the third wire trace 524 or between thesecond wire trace 522 and the third wire trace 524. In a particularembodiment, the width (b) of the MTJ stack 506 illustrated in FIG. 5 isgreater than the depth (d), and respective magnetic domains carried by afree layer within the MTJ stack 506 adjacent to the lateral electrodes510 and 512 extend in a direction that is substantially parallel to thesurface 660 of the substrate 502 in a direction of the width (b) of thestack 506 (i.e., into or out from the page view of FIG. 6). If width (b)of the MTJ stack 506 is smaller than the depth (d), respective magneticfields of free layer within the MTJ stack 506 adjacent to the lateralelectrode 510 and 512 may be vertical along the trench depth direction.

FIG. 7 is a cross-sectional diagram 700 of the circuit device 500 ofFIG. 5 taken along line 7-7 in FIG. 5. The diagram 700 includes thesubstrate 502 having the second inter-layer dielectric layer 632, thefirst cap layer 634, the third inter-layer dielectric layer 636, thesecond cap layer 638, the third cap layer 640, the fourth inter-layerdielectric layer 642, and the fifth inter-layer dielectric layer 644.The substrate 502 includes the MTJ stack 506, the top electrode 508, anda center via 516 that extends from the third wire trace 524 to the topelectrode 508. The substrate 502 also includes the process opening 526,which may be formed by selectively removing a portion of the MTJstructure 504 and filled by depositing an inter-layer dielectricmaterial within the processing opening 526.

In a particular illustrative embodiment, the MTJ structure 504 is asubstantially u-shaped structure including three sidewalls and a bottomwall. The MTJ structure 504 can include lateral electrodes, such as thefirst and second lateral electrodes 510 and 512, that are associatedwith respective sidewalls and can include a bottom electrode that isassociated with the bottom wall. Additionally, the MTJ structure 504 isadapted to store up to four unique data bits.

FIG. 8 is top view of a third particular illustrative embodiment of acircuit device 800 including an MTJ cell having multiple lateralmagnetic domains. The circuit device 800 includes a substrate 802. Thesubstrate 802 includes a magnetic tunnel junction (MTJ) structure 804that has an MTJ stack 806, a center electrode 808, a first lateralelectrode 810, a second lateral electrode 812, and a third lateralelectrode 1050. The MTJ stack 806 has a length (a) and a width (b),where the length (a) is greater than the width (b). The substrate 802includes a first via 814 coupled to the first lateral electrode 810, acenter via 816 coupled to the center electrode 808, a second via 818coupled to the second lateral electrode 812, and a third via 827 coupledto the third lateral electrode 1050. The substrate 802 also includes afirst wire trace 820 coupled to the first via 814, a second wire trace822 coupled to the second via 818, and a third wire trace 824 coupled tothe center via 816. The substrate 802 also includes a process opening826. The substrate 802 also includes a fourth wire trace 828 coupled toa third via 827. In a particular embodiment, the MTJ structure 804 isadapted to store a first data bit value within a first portion freelayer of the MTJ stack 806 that is adjacent to the first lateralelectrode 810, a second data bit value within a second portion of thefree layer that is adjacent to the second lateral electrode 812, and athird data bit value within a third portion of the free layer that isadjacent to the third lateral electrode 1050.

FIG. 9 is a cross-sectional diagram 900 of the circuit device 800 ofFIG. 8 taken along line 9-9 in FIG. 8. The diagram 900 illustrates thesubstrate 802 including a first inter-layer dielectric layer 930, asecond inter-layer dielectric layer 932, a first cap layer 934, a thirdinter-layer dielectric layer 936, a second cap layer 938, a third caplayer 940, a fourth inter-layer dielectric layer 942, and a fifthinter-layer dielectric layer 944. The substrate 802 includes a firstsurface 960 and a second surface 970. The substrate 802 also includesthe MTJ structure 804 including the MTJ stack 806. The first lateralelectrode 810, the second lateral electrode 812, and the MTJ stack 806are disposed within a trench in the substrate 802. The trench has adepth (d). The substrate 802 includes the third wire trace 824 depositedand patterned at the first surface 960 and includes the first and secondwire traces 820 and 822 deposited and patterned at the second surface970. The first wire trace 820 is coupled to the first via 814, whichextends from the first wire trace 820 to the first lateral electrode810. The second wire trace 822 is coupled to the second via 818, whichextends from the second wire trace 822 to the second lateral electrode812. The third wire trace 824 is coupled to the center via 816, whichextends from the third wire trace 824 to the center (top) electrode 808.The center electrode 808 is coupled to the MTJ stack 806.

In general, the MTJ stack 806 is adapted to store a first data bit valuewithin a first portion of the free layer of the MTJ stack 806 that isadjacent to the first lateral electrode 810. The MTJ stack 806 is alsoadapted to store a second data bit value within a second portion of thefree layer of the MTJ stack 806 that is adjacent to the second lateralelectrode 812. The MTJ stack 806 is also adapted to store a third databit value within a third portion of the free layer of the MTJ stack 806that is adjacent to the third lateral electrode 1050. A data value canbe read from the MTJ stack 806 by applying a voltage between the thirdwire trace 824 and the first wire trace 820, the second wire trace 822,or the fourth wire trace 828 and by comparing a current at the thirdwire trace 824 or at the first wire trace 820, the second wire trace822, or the fourth wire trace 828 to a reference current. Alternatively,a data value may be written to the MTJ stack 806 by applying a writecurrent between the first wire trace 820, or the second wire trace 822,or the fourth wire trace 828, and the third wire trace 824. In aparticular embodiment, the length (a) and the width (b) of the MTJ stack806 illustrated in FIG. 8 are greater than the depth (d), and respectivemagnetic domains carried by a free layer within the MTJ stack 806adjacent to the lateral electrodes 810, 812, and 1050 extend in adirection that is substantially parallel to the surface 960 of thesubstrate 802 in a direction of the width (h) or length (a) of the MTJstack 806 (i.e., into or out from the page view of FIG. 9). If thelength (a) and width (b) of the MTJ stack 806 are smaller than the depth(d), respective magnetic fields of free layer within the MTJ stack 806adjacent to the lateral electrodes 810, 812, and 1050 may be verticalalong the trench depth direction.

FIG. 10 is a cross-sectional diagram 1000 of the circuit device 800 ofFIG. 8 taken along line 10-10 in FIG. 8. The diagram 1000 includes thesubstrate 802 having the first inter-layer dielectric layer 930, thesecond inter-layer dielectric layer 932, the first cap layer 934, thethird inter-layer dielectric layer 936, the second cap layer 938, thethird cap layer 940, the fourth inter-layer dielectric layer 942, andthe fifth inter-layer dielectric layer 944. The substrate 802 includesthe MTJ stack 806, the top electrode 808, and a center via 816 thatextends from the third wire trace 824 to the top electrode 808. Thesubstrate 802 also includes the process opening 826, which may be formedby selectively removing a portion of the MTJ structure 804 and filled bydepositing an inter-layer dielectric material within the processingopening 826. The substrate 802 also includes the fourth wire trace 828coupled to the third via 827, which extends from the fourth wire trace828 to a third lateral electrode 1050, which is coupled to the MTJ stack806.

In a particular illustrative embodiment, the MTJ structure 804 is asubstantially u-shaped structure including three sidewalls and a bottomwall. In the cross-sectional view of FIG. 10, the MTJ stack 806 is anL-shaped structure. The MTJ structure 804 can include lateralelectrodes, such as the first, second, and third lateral electrodes 810,812, and 1050, that are associated with respective sidewalls and caninclude a bottom electrode (not shown) that is associated with thebottom wall. Additionally, the MTJ structure 804 is adapted to store upto four unique data bits.

FIG. 11 is top view of a fourth particular illustrative embodiment of acircuit device 1100 including an MTJ cell having multiple lateralmagnetic domains. The circuit device 1100 includes a substrate 1102. Thesubstrate 1102 includes a magnetic tunnel junction (MTJ) structure 1104that has an MTJ stack 1106, a center electrode 1108, a first lateralelectrode 1110, and a second lateral electrode 1112. The MTJ stack 1106has a length (a) and a width (b), where the length (a) is greater thanthe width (b). The substrate 1102 includes a first via 1114 coupled tothe first lateral electrode 1110, a center via 1116 coupled to thecenter electrode 1108, a second via 1118 coupled to the second lateralelectrode 1112, and a third via 1127 coupled to a third lateralelectrode 1350. The substrate 1102 also includes a first wire trace 1120coupled to the first via 1114, a second wire trace 1122 coupled to thesecond via 1118, and a third wire trace 1124 coupled to the center via1116. The substrate 1102 also includes a process opening 1126. Thesubstrate 1102 includes a third via 1127 and a fourth wire trace 1128.In a particular embodiment, the WED structure 1104 is adapted to store afirst data bit value within a first portion of the free layer of the MTJstack 1106 that is adjacent to the first lateral electrode 1110, asecond data bit value within a second portion of the free layer that isadjacent to the second lateral electrode 1112, and a third data bitvalue within a third portion of the free layer that is adjacent to thethird lateral electrode 1350.

FIG. 12 is a cross-sectional diagram 1200 of the circuit device 1100 ofFIG. 11 taken along line 12-12 in FIG. 11. The diagram 1200 illustratesthe substrate 1102 including a second inter-layer dielectric layer 1232,a first cap layer 1234, a third inter-layer dielectric layer 1236, asecond cap layer 1238, a third cap layer 1240, a fourth inter-layerdielectric layer 1242, and a fifth inter-layer dielectric layer 1244.The substrate 1102 includes a first surface 1260 and a second surface1270. The substrate 1102 also includes the MTJ structure 1104 includingthe WED stack 1106. The first lateral electrode 1110, the second lateralelectrode 1112, and the MTJ stack 1106 are disposed within a trench inthe substrate 1102. The trench has a depth (d). The substrate 1102includes the first, second, and third wire traces 1120, 1122, and 1124deposited and patterned at the first surface 1260. The fourth wire trace1128 is deposited and patterned at the second surface 1270 asillustrated in FIG. 13. The first wire trace 1120 is coupled to thefirst via 1114, which extends from the first wire trace 1120 to thefirst lateral electrode 1110. The second wire trace 1122 is coupled tothe second via 1118, which extends from the second wire trace 1122 tothe second lateral electrode 1112. The third wire trace 1124 is coupledto the center via 1116, which extends from the third wire trace 1124 tothe center (top) electrode 1108. The center electrode 1108 is coupled tothe MTJ stack 1106.

In general, the MTJ stack 1106 is adapted to store a first data bitvalue within a first portion of the free layer of the MTJ stack 1106that is adjacent to the first lateral electrode 1110. The MTJ stack 1106is also adapted to store a second data bit value within a second portionof the free layer of the MTJ stack 1106 that is adjacent to the secondlateral electrode 1112. The MTJ stack 1106 is further adapted to store athird data bit value within a third portion of the free layer of the MTJstack 1106 that is adjacent to the third lateral electrode 1350. A databit value can be read from the MTJ stack 1106 by applying a voltagebetween the third wire trace 1124 and the first wire trace 1120, thesecond wire trace 1122, or the fourth wire trace 1128, and by comparinga current at the first wire trace 1120, the second wire trace 1122 orthe fourth wire trace 1128 to a reference current. Alternatively, a databit value may be written to the MTJ stack 1106 by applying a writecurrent between the first, the second, or the fourth wire traces 1120,1122, or 1128, and the third wire trace 1124. In a particularembodiment, the length (a) and the width (b) of the MTJ stack 1106illustrated in FIG. 11 are greater than the depth (d), and respectivemagnetic domains carried by a free layer within the MTJ stack 1106adjacent to the lateral electrodes 1110, 1112, or 1350 extend in adirection that is substantially parallel to the surface 1260 of thesubstrate 1102 in a direction of the width (b) or length (a) of the MTJstack 1106 (i.e., into or out from the page view of FIG. 12). If thelength (a) and width (b) of the MTJ stack 1106 are smaller than thedepth (d), respective magnetic fields of free layer within the MTJ stack1106 adjacent to the lateral electrodes 1110, 1112, and 1350 may bevertical along the trench depth direction.

FIG. 13 is a cross-sectional diagram 1300 of the circuit device 1100 ofFIG. 11 taken along line 13-13 in FIG. 11. The diagram 1300 includes thesubstrate 1102 having a first inter-layer dielectric layer 1230, thesecond inter-layer dielectric layer 1232, the first cap layer 1234, thethird inter-layer dielectric layer 1236, the second cap layer 1238, thethird cap layer 1240, the fourth inter-layer dielectric layer 1242, andthe fifth inter-layer dielectric layer 1244. The substrate 1102 includesthe MTJ stack 1106, the top electrode 1108, and a center via 1116 thatextends from the third wire trace 1124 to the top electrode 1108. Thesubstrate 1102 also includes the process opening 1126, which may beformed by selectively removing a portion of the MTJ structure 1104 andfilled by depositing an inter-layer dielectric material within theprocessing opening 1126. The substrate 1102 also includes the fourthwire trace 1128 coupled to the third via 1127, which extends from thefourth wire trace 1128 to a third lateral electrode 1350, which iscoupled to the MTJ stack 1106.

In a particular illustrative embodiment, the MTJ structure 1104 is asubstantially u-shaped structure including three sidewalls and a bottomwall. In the cross-sectional view of FIG. 13, the MTJ stack 1106 is anL-shaped structure. The MTJ structure 1104 can include lateralelectrodes, such as the first, second, and third lateral electrodes1110, 1112, and 1350, that are associated with respective sidewalls andcan include a bottom electrode (not shown) that is associated with thebottom wall. Additionally, the MTJ structure 1104 is adapted to store upto four unique data bits.

FIG. 14 is top view of a fifth particular illustrative embodiment of acircuit device 1400 including an MTJ cell having multiple lateralmagnetic domains. The circuit device 1400 includes a substrate 1402. Thesubstrate 1402 includes a magnetic tunnel junction (MTJ) structure 1404that has an MTJ stack 1406, a center electrode 1408, a first lateralelectrode 1410, and a second lateral electrode 1412. The MTJ stack 1406has a length (a) and a width (b), where the length (a) is greater thanthe width (b). The substrate 1402 includes a first via 1414 coupled tothe first lateral electrode 1410, a center via 1416 coupled to thecenter electrode 1408, and a second via 1418 coupled to the secondlateral electrode 1412. The substrate 1402 also includes a first wiretrace 1420 coupled to the first via 1414, a second wire trace 1422coupled to the second via 1418, and a third wire trace 1424 coupled tothe center via 1416. The substrate 1402 also includes a process opening1426. In a particular embodiment, the MTJ structure 1404 is adapted tostore a first data value within a first portion and a second data valuewithin a second portion of a free layer of the MTJ stack 1406 that areadjacent to the first and second lateral electrodes 1410 and 1412,respectively.

FIG. 15 is a cross-sectional diagram 1500 of the circuit device 1400 ofFIG. 14 taken along line 15-15 in FIG. 14. The diagram 1500 illustratesthe substrate 1402 including a first inter-layer dielectric layer 1532,a first cap layer 1534, a second inter-layer dielectric layer 1536, asecond cap layer 1538, a third cap layer 1540, a third inter-layerdielectric layer 1542, and a fourth inter-layer dielectric layer 1544.The substrate 1402 includes a first surface 1560 and a second surface1570. The substrate 1402 also includes the MTJ structure 1404 includingthe MTJ stack 1406. The first lateral electrode 1410, the second lateralelectrode 1412, and the MTJ stack 1406 are disposed within a trench inthe substrate 1402. The trench has a depth (d). In this embodiment, theMTJ stack 1406 can be formed using a deposition and photo-etch processto selectively remove portions of the MTJ stack 1406. In general, aphoto-etch process may be used to remove extra MTJ film and define a MTJpattern in the illustrative embodiments depicted in FIGS. 14-25.

The substrate 1402 includes the first, second and third wire traces1420, 1422, and 1424 deposited and patterned at the first surface 1560.The first wire trace 1420 is coupled to the first via 1414, whichextends from the first wire trace 1420 to the first lateral electrode1410. The second wire trace 1422 is coupled to the second via 1418,which extends from the second wire trace 1422 to the second lateralelectrode 1412. The third wire trace 1424 is coupled to the center via1416, which extends from the third wire trace 1424 to the center (top)electrode 1408. The center electrode 1408 is coupled to the MTJ stack1406.

In general, the MTJ stack 1406 is adapted to store a first data valuewithin a first portion of a free layer of the MTJ stack 1406 that isadjacent to the first lateral electrode 1410. The MTJ stack 1406 is alsoadapted to store a second data value within a second portion of the freelayer of the MTJ stack 1406 that is adjacent to the second lateralelectrode 1412. A data value can be read from the MTJ stack 1406 byapplying a voltage between the third wire trace 1424 and the first wiretrace 1420 or the second wire trace 1422 and by comparing a current atthe first wire trace 1420 or the second wire trace 1422 to a referencecurrent. Alternatively, a data value may be written to the MTJ stack1406 by applying a write current between the first wire trace 1420 orthe second wire trace 1422 and the third wire trace 1424. In aparticular embodiment, the length (a) and the width (b) of the MTJ stack1406 illustrated in FIG. 14 are greater than the height of the MTJ stackand the depth (d), and respective magnetic domains carried by a freelayer within the MTJ stack 1406 adjacent to the lateral electrodes 1410and 1412 extend in a direction that is substantially parallel to thesurface of the substrate 1560 in a direction of the width (b) of the MTJstack 1406 (i.e., into or out from the page view of FIG. 15).

In a particular embodiment, the MTJ stack 1406 has a height (h) that isgreater than the length (a) or the width (b). In this instance,respective magnetic domains carried by a free layer within the MTJ stack1406 adjacent to the lateral electrodes 1410 and 1412 extend in adirection that is substantially perpendicular to the surface 1560 of thesubstrate 1402 in a direction of the depth (d) of the MTJ stack, 1406.

FIG. 16 is a cross-sectional diagram 1600 of the circuit device 1400 ofFIG. 14 taken along line 16-16 in FIG. 14. The diagram 1600 includes thesubstrate 1402 having the first inter-layer dielectric layer 1532, thefirst cap layer 1534, the second inter-layer dielectric layer 1536, thesecond cap layer 1538, the third cap layer 1540, the third inter-layerdielectric layer 1542, and the fourth inter-layer dielectric layer 1544.The substrate 1402 includes the MTJ stack 1406, the top electrode 1408,and a center via 1416 that extends from the third wire trace 1424 to thetop electrode 1408. The substrate 1402 also includes the process opening1426, which may be formed by selectively removing a portion of the MTJstructure 1404 and filled by depositing an inter-layer dielectricmaterial within the processing opening 1426.

In a particular illustrative embodiment, the MTJ structure 1404 is asubstantially u-shaped structure including three sidewalls and a bottomwall. The MTJ structure 1404 can include lateral electrodes, such as thefirst and second lateral electrodes 1410 and 1412, that are associatedwith respective sidewalls and can include a bottom electrode that isassociated with the bottom wall. Additionally, the MTJ structure 1404 isadapted to store up to four unique data bits.

FIG. 17 is top view of a sixth particular illustrative embodiment of acircuit device 1700 including an MTJ cell having multiple lateralmagnetic domains. The circuit device 1700 includes a substrate 1702. Thesubstrate 1702 includes a magnetic tunnel junction (MTJ) structure 1704that has an MTJ stack 1706, a center electrode 1708, a first lateralelectrode 1710, and a second lateral electrode 1712. The MTJ stack 1706has a length (a) and a width (b), where the length (a) is greater thanthe width (b). The substrate 1702 includes a first via 1714 coupled tothe first lateral electrode 1710, a center via 1716 coupled to thecenter electrode 1708, and a second via 1718 coupled to the secondlateral electrode 1712. The substrate 1702 also includes a first wiretrace 1720 coupled to the first via 1714, a second wire trace 1722coupled to the second via 1718, and a third wire trace 1724 coupled tothe center via 1716. The substrate 1702 also includes a process opening1726. In a particular embodiment, the MTJ structure 1704 is adapted tostore a first data value within a first portion and a second data valuewithin a second portion of a free layer of the MTJ stack 1706 that areadjacent to the first and second lateral electrodes 1710 and 1712,respectively.

FIG. 18 is a cross-sectional diagram 1800 of the circuit device 1700 ofFIG. 17 taken along line 18-18 in FIG. 17. The diagram 1800 illustratesthe substrate 1702 including a first inter-layer dielectric layer 1830and 1832, a first cap layer 1834, a second inter-layer dielectric layer1836, a second cap layer 1838, a third cap layer 1840, a thirdinter-layer dielectric layer 1842, and a fourth inter-layer dielectriclayer 1844. The substrate 1702 includes a first surface 1860 and asecond surface 1870. The substrate 1702 also includes the MTJ structure1704 including the MTJ stack 1706. The first lateral electrode 1710, thesecond lateral electrode 1712, and the MTJ stack 1706 are disposedwithin a trench in the substrate 1702. The trench has a depth (d), andthe MTJ stack 1706 has a height (h) that is greater than the trenchdepth (d). The substrate 1702 includes the first and second wire traces1720 and 1722 deposited and patterned at the second surface 1870, andthe third wire trace 1724 deposited and patterned at the first surface1860. The first wire trace 1720 is coupled to the first via 1714, whichextends from the first wire trace 1720 to the first lateral electrode1710. The second wire trace 1722 is coupled to the second via 1718,which extends from the second wire trace 1722 to the second lateralelectrode 1712. The third wire trace 1724 is coupled to the center via1716, which extends from the third wire trace 1724 to the center (top)electrode 1708. The center electrode 1708 is coupled to the MTJ stack1706.

In general, the MTJ stack 1706 is adapted to store a first data valuewithin a first portion of a free layer of the MTJ stack 1706 that isadjacent to the first lateral electrode 1710. The MTJ stack 1706 is alsoadapted to store a second data value within a second portion of the freelayer of the MTJ stack 1706 that is adjacent to the second lateralelectrode 1712. A data value can be read from the MTJ stack 1706 byapplying a voltage between the third wire trace 1724 and the first wiretrace 1720 or the second wire trace 1722 and by comparing a current atthe first wire trace 1720 or the second wire trace 1722 to a referencecurrent. Alternatively, a data value may be written to the MTJ stack1706 by applying a write current between the first wire trace 1720 orthe second wire trace 1722 and third wire trace 1724. In a particularembodiment, the length (a) and the width (b) of the MTJ stack 1706 aregreater than the height (h) of the MTJ stack 1706, and respectivemagnetic domains carried by a free layer within the MTJ stack 1706adjacent to the lateral electrodes 1710 and 1712 extend in a directionthat is substantially parallel to the surface 1860 of the substrate 1702in a direction of the width (b) of the MTJ stack 1706 (i.e., into or outfrom the page view of FIG. 18). In another particular embodiment, theheight (h) of the MTJ stack 1706 can be greater than the length (a) orthe width (b) and the magnetic domains carried by the free layer withinthe MTJ stack 1706 adjacent to the lateral electrodes 1710 and 1712extend in a direction that is substantially perpendicular to the surface1860 of the substrate 1702.

FIG. 19 is a cross-sectional diagram 1900 of the circuit device 1700 ofFIG. 17 taken along line 19-19 in FIG. 19. The diagram 1900 includes thesubstrate 1702 having the first inter-layer dielectric layer 1832, thefirst cap layer 1834, the second inter-layer dielectric layer 1836, thesecond cap layer 1838, the third cap layer 1840, the third inter-layerdielectric layer 1842, and the fourth inter-layer dielectric layer 1844.The substrate 1702 includes the MTJ stack 1706, the top electrode 1708,and a center via 1716 that extends from the third wire trace 1724 to thetop electrode 1708. The substrate 1702 also includes the process opening1726, which may be formed by selectively removing a portion of the MTJstructure 1704 and filled by depositing an inter-layer dielectricmaterial within the processing opening 1726.

In a particular illustrative embodiment, the MTJ structure 1704 is asubstantially u-shaped structure including three sidewalls and a bottomwall. The MTJ structure 1704 can include lateral electrodes, such as thefirst and second lateral electrodes 1710 and 1712, that are associatedwith respective sidewalls and can include a bottom electrode that isassociated with the bottom wall. Additionally, the MTJ structure 1704 isadapted to store up to four unique data bits.

FIG. 20 is top view of a seventh particular illustrative embodiment of acircuit device 2000 including an MTJ cell having multiple lateralmagnetic domains. The circuit device 2000 includes a substrate 2002. Thesubstrate 2002 includes a magnetic tunnel junction (MTJ) structure 2004that has an MTJ stack 2006, a center electrode 2008, a first lateralelectrode 2010, and a second lateral electrode 2012. The MTJ stack 2006has a length (a) and a width (b), where the length (a) is greater thanthe width (b). The substrate 2002 includes a first via 2014 coupled tothe first lateral electrode 2010, a center via 2016 coupled to thecenter electrode 2008, a second via 2018 coupled to the second lateralelectrode 2012, and a third via 2027 coupled to a third lateralelectrode 2250 depicted in FIG. 22. The substrate 2002 also includes afirst wire trace 2020 coupled to the first via 2014, a second wire trace2022 coupled to the second via 2018, and a third wire trace 2024 coupledto the center via 2016. The substrate 2002 also includes a processopening 2026. The substrate 2002 includes a third via 2027 and a fourthwire trace 2028. In a particular embodiment, the MTJ structure 2004 isadapted to store a first data value, a second data value, and a thirddata value within respective portions of a free layer of the MTJ stack2006 that are adjacent to the first, the second, and the third lateralelectrodes 2010, 2012, and 2250.

FIG. 21 is a cross-sectional diagram 2100 of the circuit device 2000 ofFIG. 20 taken along line 21-21 in FIG. 20. The diagram 2100 illustratesthe substrate 2002 including a first inter-layer dielectric layer 2130,a second inter-layer dielectric layer 2132, a first cap layer 2134, athird inter-layer dielectric layer 2136, a second cap layer 2138, athird cap layer 2140, a fourth inter-layer dielectric layer 2142, and afifth inter-layer dielectric layer 2144. The substrate 2002 includes afirst surface 2160 and a second surface 2170. The substrate 2002 alsoincludes the MTJ structure 2004 including the MTJ stack 2006. The firstlateral electrode 2010, the second lateral electrode 2012, and the MTJstack 2006 are disposed within a trench in the substrate 2002. Thetrench has a depth (d). The MTJ stack 2006 has a height (h) that isgreater than the trench depth (d). The substrate 2002 includes the firstand second wire traces 2020 and 2022 at the second surface 2170, and thethird wire trace 2024 at the first surface 2160. The fourth wire trace2028 is also deposited and patterned at the second surface 2170 (asshown in FIG. 22). The first wire trace 2020 is coupled to the first via2014, which extends from the first wire trace 2020 to the first lateralelectrode 2010. The second wire trace 2022 is coupled to the second via2018, which extends from the second wire trace 2022 to the secondlateral electrode 2012. The third wire trace 2024 is coupled to thecenter via 2016, which extends from the third wire trace 2024 to thecenter (top) electrode 2008. The center electrode 2008 is coupled to theMTJ stack 2006.

In general, the MTJ stack 2006 is adapted to store a first data valuewithin a first portion of a free layer of the MTJ stack 2006 that isadjacent to the first lateral electrode 2010. The MTJ stack 2006 is alsoadapted to store a second data value within a second portion of the freelayer of the MTJ stack 2006 that is adjacent to the second lateralelectrode 2012. A data value can be read from the MTJ stack 2006 byapplying a voltage between the third wire trace 2024 and the first wiretrace 2020, the second wire trace 2022, or the fourth wire trace 2250,and by comparing a current at the first wire trace 2020, the second wiretrace 2022, or the fourth wire trace 2250 to a reference current.Alternatively, a data value may be written to the MTJ stack 2006 byapplying a write current between the first wire trace 2020, the secondwire trace 2022 or the fourth wire trace 2250 and the third wire trace2024. In a particular embodiment, the length (a) and the width (b) ofthe MTJ stack 2006 illustrated in FIG. 20 are greater than the height(h), and respective magnetic domains carried by a free layer within theMTJ stack 2006 adjacent to the lateral electrodes 2010 and 2012 extendin a direction that is substantially parallel to the surface 2160 of thesubstrate 2002 in a direction of the width (b) of the MTJ stack 2006(i.e., into or out from the page view of FIG. 21). In another particularembodiment, the height (h) of the MTJ stack 2006 can be greater than thelength (a) or the width (b) and the magnetic domains carried by the freelayer within the MTJ stack 2006 adjacent to the lateral electrodes 2110and 2112 extend in a direction that is substantially perpendicular tothe surface 2160 of the substrate 2002.

FIG. 22 is a cross-sectional diagram 2200 of the circuit device 2000 ofFIG. 20 taken along line 22-22 in FIG. 20. The diagram 2200 includes thesubstrate 2002 having the first inter-layer dielectric layer 2130, thesecond inter-layer dielectric layer 2132, the first cap layer 2134, thethird inter-layer dielectric layer 2136, the second cap layer 2138, thethird cap layer 2140, the fourth inter-layer dielectric layer 2142, andthe fifth inter-layer dielectric layer 2144. The substrate 2002 includesthe MTJ stack 2006, the top electrode 2008, and a center via 2016 thatextends from the third wire trace 2024 to the top electrode 2008. Thesubstrate 2002 also includes the process opening 2026, which may beformed by selectively removing a portion of the MTJ structure 2004 andfilled by depositing an inter-layer dielectric material within theprocessing opening 2026. The substrate 2002 also includes the fourthwire trace 2028 deposited and patterned at the second surface 2170. Thefourth wire trace 2028 is coupled to the third via 2027, which extendsfrom the fourth wire trace 2028 to a third lateral electrode 2250, whichis coupled to the MTJ stack 2006.

In a particular illustrative embodiment, the MTJ structure 2004 is asubstantially u-shaped structure including three sidewalls and a bottomwall. In the cross-sectional view of FIG. 22, the MTJ stack 2006 is anL-shaped structure. The MTJ structure 2004 can include lateralelectrodes, such as the first, second, and third lateral electrodes2010, 2012, and 2250, that are associated with respective sidewalk andcan include a bottom electrode (not shown) that is associated with thebottom wall. Additionally, the MTJ structure 2004 is adapted to store upto four unique data bits.

FIG. 23 is top view of an eighth particular illustrative embodiment of acircuit device 2300 including MTJ cell having multiple lateral magneticdomains. The circuit device 2300 includes a substrate 2302. Thesubstrate 2302 includes a magnetic tunnel junction (MTJ) structure 2304that has an MTJ stack 2306, a center electrode 2308, a first lateralelectrode 2310, and a second lateral electrode 2312. The MTJ stack 2306has a length (a) and a width (b), where the length (a) is greater thanthe width (b). The substrate 2302 includes a first via 2314 coupled tothe first lateral electrode 2310, a center via 2316 coupled to thecenter electrode 2308, and a second via 2318 coupled to the secondlateral electrode 2312. The substrate 2302 also includes a first wiretrace 2320 coupled to the first via 2314, a second wire trace 2322coupled to the second via 2318, and a third wire trace 2324 coupled tothe center via 2316. The substrate 2302 also includes a process opening2326. The substrate 2302 includes a third via 2327 and a fourth wiretrace 2328. In a particular embodiment, the MTJ structure 2304 isadapted to store a first data value, a second data value, and a thirddata value within portions of a free layer of the MTJ stack 2306 thatare adjacent to the first, second, and a third lateral electrodes 2310,2312, and 2550, respectively.

FIG. 24 is a cross-sectional diagram 2400 of the circuit device 2300 ofFIG. 23 taken along line 24-24 in FIG. 23. The diagram 2400 illustratesthe substrate 2302 including a first inter-layer dielectric layer 2430,a second inter-layer dielectric layer 2432, a first cap layer 2434, athird inter-layer dielectric layer 2436, a second cap layer 2438, athird cap layer 2440, a fourth inter-layer dielectric layer 2442, and afifth inter-layer dielectric layer 2444. The substrate 2302 includes afirst surface 2460 and a second surface 2470. The substrate 2302 alsoincludes the MTJ structure 2304 including the MTJ stack 2306. The firstlateral electrode 2310, the second lateral electrode 2312, and the MTJstack 2306 are disposed within a trench in the substrate 2302. Thetrench has a depth (d). The substrate 2302 includes the first, second,and third wire traces 2320, 2322, and 2324 disposed at the first surface2460. The fourth wire trace 2328 is disposed at the second surface 2470(depicted in FIG. 25). The first wire trace 2320 is coupled to the firstvia 2314, which extends from the first wire trace 2320 to the firstlateral electrode 2310. The second wire trace 2322 is coupled to thesecond via 2318, which extends from the second wire trace 2322 to thesecond lateral electrode 2312. The third wire trace 2324 is coupled tothe center via 2316, which extends front the third wire trace 2324 tothe center (top) electrode 230$. The center electrode 2308 is coupled tothe MTJ stack 2306.

In general, the MTJ stack 2306 is adapted to store a first data valuewithin a first portion of a free layer of the MTJ stack 2306 that isadjacent to the first lateral electrode 2310. The MTJ stack 2306 is alsoadapted to store a second data value within a second portion of the freelayer of the MTJ stack 2306 that is adjacent to the second lateralelectrode 2312. The MTJ stack 2306 is also adapted to store a third datavalue within a third portion of the free layer of the MTJ stack 2306that is adjacent to the third lateral electrode 2550. A data value canbe read from the MTJ stack 2306 by applying a voltage between the thirdwire trace 2324 and the first wire trace 2320, the second wire trace2322, or the fourth wire trace 2328 and by comparing a current at thefirst wire trace 2320, the second wire trace 2322, or the fourth wiretrace 2328 to a reference current. Alternatively, a data value may bewritten to the MTJ stack 2306 by applying a voltage current between thefirst wire trace 2320, the second wire trace 2322, or the fourth wiretrace 2328 and third wire trace 2324. In a particular embodiment, thelength (a) and the width (b) of the MTJ stack 2306 illustrated in FIG.23 are greater than the height (h), and respective magnetic domainscarried by a free layer within the MTJ stack 2306 adjacent to thelateral electrodes 2310 and 2312 extend in a direction that issubstantially parallel to the surface 2460 of the substrate 2302 in adirection of the width (b) of the MTJ stack 2306 (i.e., into or out fromthe page view). In another particular embodiment, the height (h) of theMTJ stack 2306 can be greater than the length (a) or the width (b) andthe magnetic domains carried by the free layer within the MTJ stack 2306adjacent to the lateral electrodes 2310 and 2312 extend in a directionthat is substantially perpendicular to the surface 2460 of the substrate2302.

FIG. 25 is a cross-sectional diagram 2500 of the circuit device 2300 ofFIG. 23 taken along line 25-25 in FIG. 23. The diagram 2500 includes thesubstrate 2302 having the first inter-layer dielectric layer 2430, thesecond inter-layer dielectric layer 2432, the first cap layer 2434, thethird inter-layer dielectric layer 2436, the second cap layer 2438, thethird cap layer 2440, the fourth inter-layer dielectric layer 2442, andthe fifth inter-layer dielectric layer 2444. The substrate 2302 includesthe MTJ stack 2306, the top electrode 2308, and a center via 2316 thatextends from the third wire trace 2324 to the top electrode 2308. Thesubstrate 2302 also includes the process opening 2326, which may beformed by selectively removing a portion of the MTJ structure 2304 andfilled by depositing an inter-layer dielectric material within theprocessing opening 2326. The substrate 2302 also includes the fourthwire trace 2328 coupled to the third via 2327, which extends from thefourth wire trace 2328 to a third lateral electrode 2550, which iscoupled to the MTJ stack 2306.

In a particular illustrative embodiment, the MTJ structure 2304 is asubstantially u-shaped structure including three sidewalls and a bottomwall. In the cross-sectional view of FIG. 25, the MTJ stack 2306 is anL-shaped structure. The MTJ structure 2304 can include lateralelectrodes, such as the first, second, and third lateral electrodes2310, 2312, and 2550, that are associated with respective sidewalls andcan include a bottom electrode (not shown) that is associated with thebottom wall. Additionally, the MTJ structure 2304 is adapted to store upto four unique data bits.

FIG. 26 is a top view of a free layer 2600 of an MTJ cell havingmultiple lateral magnetic domains configured in a zero-value state. Inthis example, the free layer 2600 is illustrated in a bit-zero state,where each of the bits represents a zero value. The free layer 2600includes a first sidewall 2602, a second sidewall 2604, a third sidewall2606, and a bottom wall 2608. The free layer 2600 of each of thesidewalls 2602, 2604, and 2606 and of the bottom wall 2608 carry uniquemagnetic domains configured to represent a data value, such as a “1” ora “0” value. The first sidewall 2602 carries a first magnetic domain2612. The second sidewall 2604 carries a second magnetic domain 2614.The third sidewall 2606 carries a third magnetic domain 2616. The bottomwall 2608 carries a fourth magnetic domain 2618. The magnetic domains2612, 2614, and 2616 extend out from the page view as indicated by thedots (i.e., an arrow head). In this particular instance, a depth of eachof the sidewalls 2602, 2604, and 2606 is greater than a respectivelength or width of each of the sidewalls 2602, 2604, and 2606.Accordingly, the magnetic domains 2612, 2614, and 2616 are oriented in adirection of the depth.

The first magnetic domain 2612 of the first sidewall 2602 is separatedfrom the second magnetic domain 2614 of the second sidewall 2604 by afirst domain barrier 2630. Similarly, the second magnetic domain 2614 ofthe second sidewall 2604 is separated from the third magnetic domain2616 of the third sidewall 2606 by a second domain barrier 2632.

In general, the first domain barrier 2630 and the second domain barrier2632 represent domain walls, which are interfaces that separate magneticdomains, such as the magnetic domains 2612, 2614, and 2616,respectively. The first and second domain barriers 2630 and 2632represent transitions between different magnetic moments. In aparticular embodiment, the first and second domain barriers 2630 and2632 may represent a change in a magnetic moment where a magnetic fieldundergoes an angular displacement of 0 or 180 degrees.

The direction of a magnetic field associated with the first magneticdomain 2612 (i.e., a direction of a magnetic field within the free layer2600 at the first sidewall 2602) may be altered using a first writecurrent 2622. Similarly, a direction of a magnetic field associated withthe second magnetic domain 2614 carried by the free layer 2600 of thesecond sidewall 2604 may be altered using a second write current 2624. Adirection of a magnetic field associated with the third magnetic domain2616 that is carried by the free layer 2600 at the third sidewall 2606may be altered using a third write current 2626. A direction of amagnetic field associated with the fourth magnetic domain 2618 carriedby the free layer 2600 at the bottom wall 2608 may be altered using afourth write current 2628.

In general, a relative direction of the magnetic field carried by thefree layer 2600 relative to a fixed magnetic field in the fixed layer(such as the free layer 2704 relative to fixed layer 2708 illustrated inFIG. 27) of each of the sidewalls 2602, 2604 and 2606 and of the bottomwall 2608 determines the bit value. In the example shown, magneticorientations of the fixed layer and of the free layer 2600 are inparallel (as illustrated by magnetic fields 2714 and 2716 in FIG. 27).Accordingly, each of the write currents 2622, 2624, 2626 and 2628 mayrepresent write “0” currents, altering a direction of the magnetic fieldassociated with the respective magnetic domains 2612, 2614, 2616 and2618 within the free layer 2600 to represent a reset or “0” state.

FIG. 27 is a cross-sectional view of an MTJ cell 2700 including the freelayer 2600 of the sidewall 2602 of FIG. 26 illustrating a write currentto configure the magnetic domains of the free layer to represent a zerovalue. The MTJ cell 2700 includes a top electrode 2702, a free layer2704 (i.e., the free layer 2612 in FIG. 26), a magnetic tunnel junctiontunnel barrier 2706, a fixed layer 2708, an anti-ferromagnetic (AF)layer 2712, and a bottom electrode 2710. In general, the top electrode2702 and the bottom electrode 2710 are electrically conductive layersadapted to carry an electrical current. The fixed layer 2708 is aferromagnetic layer that has been annealed to fix a direction of amagnetic field 2716 within the fixed (pinned) layer 2708. The free layer2704 is a ferromagnetic layer having a magnetic field that can bechanged by a write current. The MTJ tunnel barrier or barrier layer 2706may be formed from an oxide of metal material. The direction of amagnetic field 2714 within the free layer 2704 may be changed using thewrite current 2622. The direction of the magnetic field 2716 within thefixed layer 2708 is pinned by the anti-ferromagnetic (AF) layer 2712.

A direction of the magnetic fields in the free layer 2704 relative tothe fixed magnetic field of the fixed layer 2708 indicates whether thedata bit stored at the free layer 2704 of the particular MTJ cell 2700is a bit value of “1” or bit value of “0.” The magnetic direction of themagnetic field in the free layer 2704, generally indicated at 2714, maybe changed using the write current 2622. As shown, the write current2622 represent a write 0 current that flows from the top electrode 2702through the free layer 2704 across the magnetic tunnel junction barrier2706 through the fixed layer 2708 and through the anti-ferromagnetic(AF) layer 2712 and through the bottom electrode 2710. The MTJ cell 2700may also include additional layers (not shown) for seed layer,connection, or performance enhancement purposes. In an illustrativeembodiment, any or all of the embodiments illustrated in FIGS. 1-34 mayinclude a MTJ stack structure substantially similar to the MTJ stackstructure of the kill cell 2700.

FIG. 28 is cross-sectional view of the free layer of FIG. 26 taken alongline 28-28 in FIG. 26. FIG. 28 is a cross-sectional view 2800 of thefree layer 2600 taken along line 28-28 in FIG. 26. The free layer 2600includes the first sidewall 2602, the third sidewall 2606 and the bottomwall 2608. In this example, a direction of a first magnetic domaincarried by the free layer 2600 at the first sidewall 2602, as indicatedat 2612, extends in a direction of a depth (d) of the first sidewall2602, which corresponds to the arrow 2612. A direction of a thirdmagnetic domain carried by the free layer of the third sidewall 2606, asindicated at 2616, extends in a direction of the depth (d) of the thirdsidewall 2606, which corresponds to the arrow 2616. In this example, thefirst and third magnetic domains 2612 and 2616 may extend in a directionthat is substantially perpendicular to a surface of a substrate. Thefourth magnetic domain 2618 associated with the bottom wall 2608 extendsin a direction that is substantially perpendicular to the first andthird magnetic domains 2612 and 2616 and substantially parallel to thesurface of the substrate. Additionally the fourth magnetic domain 2618extends in a direction into the page, as indicated by the tail of anarrow (asterisk).

The free layer 2600 includes a first domain barrier (wall) 2840 and asecond domain barrier 2842. In a particular example, the first domainbarrier 2840 may correspond to a structural interface between the firstsidewall 2602 and the bottom wall 2608. The first domain barrier 2840isolates a first magnetic domain 2612 of the free layer 2600 at thefirst sidewall 2602 from a fourth magnetic domain 2618 of the bottomwall 2600. The second domain barrier 2842 may correspond to a structuralinterface between the bottom wall 2608 and the third sidewall 2606. Thesecond domain barrier 2842 isolates a magnetic domain 2616 of a freelayer of the third sidewall 2606 from the magnetic domain 2618 of thefree layer 2600 associated with the bottom wall 2608.

In the embodiment illustrated in FIG. 28, the free layer 2600 may beadapted to store at least three data bits. A first data bit may berepresented by a direction of the first magnetic domain 2612 carried bythe free layer 2600 at the first sidewall 2602. A second data bit may berepresented by the fourth magnetic domain 2618 carried by the free layer2600 at the bottom wall 2608. A third data bit may be represented by thethird magnetic domain 2616 carried by the free layer 2600 at the thirdsidewall 2606. The write currents 2622, 2626, and 2628 may be applied toselectively alter an orientation of a corresponding magnetic domain2612, 2616, and/or 2618 of a selected sidewall without altering theorientation of the magnetic domain associated with the other sidewall orof the bottom wall 2608, for example.

FIG. 29 is a diagram of a cross-sectional view 2900 of the free layer2600 illustrated in FIG. 26, taken along lines 29-29. The free layer2600 includes the sidewall 2604 and the bottom wall 2608. In thisparticular example, the five layer 2600 includes a magnetic domainbarrier 2950. The magnetic domain barrier (or wall) 2950 isolates themagnetic domain 2618 carried by the free layer 2600 at the bottom wall2608 from the magnetic domain 2614 carried by the free layer 2600 at thesecond sidewall 2604. The domain barrier 2950 may correspond to astructural interface between the sidewall 2604 and the bottom wall 2608.The second magnetic domain 2614 extends in a direction that correspondsto a depth (d) of the sidewall 2604 (i.e., in a direction that issubstantially normal to a surface of a substrate). The fourth magneticdomain 2618 extends in a direction that is substantially perpendicularto the second magnetic domain 2614 and to the depth (d) and in adirection that is parallel to a width (b) of an MTJ cell. The depth (d)(as illustrated in FIGS. 2-13) or height (h) (as illustrated in FIGS.14-25) may represent a trench depth or may represent a height of thesidewall.

In a particular illustrative embodiment, the domain barriers 2630 and2632 illustrated in FIG. 26, the domain barriers 2840 and 2842illustrated in FIG. 28, and the domain barrier 2950 illustrated in FIG.29 allow the free layer 2600 to store multiple data bits. In particular,the free layer 2600 illustrated in FIG. 26 may be adapted to store up tofour data bits, which may be represented by the magnetic domains 2612,2614, 2616 and 2618, illustrated in FIGS. 26, 28, and 29.

FIG. 30 is a top view of a five layer 3000 of an MTJ cell havingmultiple lateral magnetic domains configured in a one-value state. Inthis example, the free layer 3000 is illustrated in a bit-one state,where each of the bits represents a one value (i.e., a logical “1”value). The free layer 3000 includes a first sidewall 3002, a secondsidewall 3004, a third sidewall 3006, and a bottom wall 3008. The fivelayer 3000 of each of the sidewalls 3002, 3004, and 3006 and of thebottom wall 3008 carry unique magnetic domains configured to represent adata value, such as a “1” or a “0” value. The first sidewall 3002carries a first magnetic domain 3012. The second sidewall 3004 carries asecond magnetic domain 3014. The third sidewall 3006 carries a thirdmagnetic domain 3016. The bottom wall 3008 carries a fourth magneticdomain 3018. The magnetic domains 3012, 3014, and 3016 extend into thepage as indicated by asterisks (i.e., tail of an arrow). In thisparticular instance, a depth of each of the sidewalls 3002, 3004, and3006 is greater than a respective length or width of each of thesidewalls 3002, 3004, and 3006. Accordingly, the magnetic domains 3012,3014, and 3016 are oriented lengthwise in a direction of the depth.

The first magnetic domain 3012 of the first sidewall 3002 is separatedfrom the second magnetic domain 3014 of the second sidewall 3004 by afirst domain barrier 3030. Similarly, the second magnetic domain 3014 ofthe second sidewall 3004 is separated from the third magnetic domain3016 of the third sidewall 3006 by a second domain harrier 3032.

In general, the first domain barrier 3030 and the second domain barrier3032 represent domain walls, which are interfaces that separate magneticdomains, such as the magnetic domains 3012, 3014, and 3016,respectively. The first and second domain barriers 3030 and 3032represent transitions between different magnetic moments. In aparticular embodiment, the first and second domain barriers 3030 and3032 may represent a change in a magnetic moment where a magnetic fieldundergoes an angular displacement of 0 or 180 degrees.

The direction of a magnetic field associated with the first magneticdomain 3012 (i.e., a direction of a magnetic field within the free layer3000 at the first sidewall 3002) may be altered using a first writecurrent 3022. Similarly, a direction of a magnetic field associated withthe second magnetic domain 3014 carried by the free layer 3000 of thesecond sidewall 3004 may be altered using a second write current 3024. Adirection of a magnetic field associated with the third magnetic domain3016 that is carried by the free layer 3000 at the third sidewall 3006may be altered using a third write current 3026. A direction of amagnetic field associated with the fourth magnetic domain 3018 carriedby the five layer 3000 at the bottom wall 3008 may be altered using afourth write current 3028.

In general, a relative direction of the magnetic field carried by thefree layer 3000 relative to a fixed magnetic field in the fixed layer(such as the free layer 3104 relative to fixed layer 3108 illustrated inFIG. 31) of each of the sidewalls 3002, 3004 and 3006 and of the bottomwall 3008 determines the bit value. In the example shown, magneticorientations of the fixed layer and of the free layer 3000 areanti-parallel (as illustrated by magnetic fields 3114 and 3116 in FIG.31). Accordingly, each of the write currents 3022, 3024, 3026 and 3028may represent write “1” currents, altering a direction of the magneticfield associated with the respective magnetic domains 3012, 3014, 3016and 3018 within the free layer 3000 to represent a reset or “1” state.

FIG. 31 is a cross-sectional view of an MTJ cell 3100 including the freelayer 3000 of the sidewall 3002 of FIG. 30 illustrating a write currentto configure the magnetic domains of the free layer to represent a onevalue. The MTJ cell 3100 includes a top electrode 3102, a free layer3104 (i.e., the free layer 3012 in FIG. 30), a magnetic tunnel junctiontunnel barrier 3106, a fixed layer 3108, an anti-ferromagnetic (AF)layer 3112, and a bottom electrode 3110. In general, the top electrode3102 and the bottom electrode 3110 are electrically conductive layersadapted to carry an electrical current. The fixed layer 3108 is aferromagnetic layer that has been annealed to fix a direction of amagnetic field 3116 within the fixed (pinned) layer 3108. The free layer3104 is a ferromagnetic layer that can be programmed. The MTJ tunnelbarrier or barrier layer 3106 may be formed from an oxide of metalmaterial. The direction of a magnetic field 3114 within the free layer3104 may be changed using the write current 3022. The magnetic field3116 of the fixed layer 3108 is pinned by the anti-ferromagnetic (AF)layer 3112.

A direction of the magnetic fields in the free layer 3104 relative tothe fixed magnetic field of the fixed layer 3108 indicates whether thedata bit stored at the free layer 3104 of the particular MTJ cell 3100is a bit value of “1” or bit value of “0.” The magnetic direction of themagnetic field in the free layer 3104, generally indicated at 3114, maybe changed using the write current 3022. As shown, the write current3022 represents a write “1” current that flows from the bottom electrode3110 through the AF layer 3112 through the fixed layer 3108 across themagnetic tunnel junction barrier 3106 through the free layer 3104 andthrough the top electrode 3102. The MTJ cell 3100 may include additionallayers (not shown) for seed layer, connection, or performanceenhancement purposes. In an illustrative embodiment, any MTJ stackdepicted in FIGS. 1-34 may include a structure substantially similar tothe MTJ cell 3100.

FIG. 32 is a cross-sectional view 3200 of the free layer 3000 takenalong line 32-32 in FIG. 30. The free layer 3000 includes the firstsidewall 3002, the third sidewall 3006 and the bottom wall 3008. In thisexample, a direction of a first magnetic domain carried by the freelayer 3000 at the first sidewall 3002, as indicated at 3012, extends ina direction of a depth (d) of the first sidewall 3002, which correspondsto the arrow 3012. A direction of a third magnetic domain carried by thefree layer of the third sidewall 3006, as indicated at 3016, extends ina direction of the depth (d) of the third sidewall 3006, whichcorresponds to the arrow 3016. In this example, the first and thirdmagnetic domains 3012 and 3016 may extend in a direction that issubstantially perpendicular to a surface of a substrate. The fourthmagnetic domain 3018 associated with the bottom wall 3008 extends in adirection that is substantially perpendicular to the first and thirdmagnetic domains 3012 and 3016 and substantially parallel to the surfaceof the substrate. Additionally the fourth magnetic domain 3018 extendsin a direction out from the page view, as indicated by the arrow head(dot).

The free layer 3000 includes a first domain barrier (wall) 3240 and asecond domain barrier 3242. In a particular example, the first domainbarrier 3240 may correspond to a structural interface between the firstsidewall 3002, and the bottom wall 3008. The first domain barrier 3240isolates a first magnetic domain 3012 of the free layer 3000 at thefirst sidewall 3002 from a fourth magnetic domain 3018 of the bottomwall 3008. The second domain barrier 3242 may correspond to a structuralinterface between the bottom wall 3008 and the third sidewall 3006. Thesecond domain barrier 3242 isolates a magnetic domain 3016 of a freelayer of the third sidewall 3006 from the magnetic domain 3018 of thefree layer 3000 associated with the bottom wall 3008.

In the embodiment illustrated in FIG. 32, the free layer 3000 may beadapted to store at least three data bits. A first data bit may berepresented by a direction of the first magnetic domain 3012 carried bythe free layer 3000 at the first sidewall 3002. A second data bit may berepresented by the fourth magnetic domain 3018 carried by the free layer3000 at the bottom wall 3008. A third data bit may be represented by thethird magnetic domain 3016 carried by the free layer 3000 at the thirdsidewall 3006. The write currents 3022, 3026, and 3028 may be applied toselectively alter an orientation of a corresponding magnetic domain3012, 3016, and/or 3018 of a selected sidewall without altering theorientation of the magnetic domain associated with the other sidewall orof the bottom wall 3008, for example.

FIG. 33 is a diagram of a cross-sectional view 3300 of the free layer3000 illustrated in FIG. 30, taken along lines 33-33. The free layer3000 includes the sidewall 3004 and the bottom wall 3008. In thisparticular example, the free layer 3000 includes magnetic domainsbarrier 3350. The magnetic domain barrier (or wall) 3350 isolates themagnetic domain 3018 carried by the free layer 3000 at the bottom wall3008 from the magnetic domain 3014 carried by the free layer 3000 at thesecond sidewall 3004. The domain barrier 3350 may correspond to astructural interface between the sidewall 3004 and the bottom wall 3008.The second magnetic domain 3014 extends in a direction that correspondsto a depth (d) of the sidewall 3004 (i.e., in a direction that issubstantially normal to a surface of a substrate). The fourth magneticdomain 3018 extends in a direction that is substantially perpendicularto the second magnetic domain 3014 and to the depth (d) and in adirection that is parallel to a width (b) of the MTJ cell. The depth (d)or height (h) may represent a trench depth or may represent a height ofthe sidewall.

In a particular illustrative embodiment, the domain barriers 3030 and3032 illustrated in FIG. 30, the domain barriers 3240 and 3242illustrated in FIG. 32, and the domain barrier 3350 illustrated in FIG.33 allow the free layer 3000 to store multiple data bits. In particular,the free layer 3000 illustrated in FIG. 30 may be adapted to store up tofour data bits, which may be represented by the magnetic domains 3012,3014, 3016, and 3018, illustrated in FIGS. 30, 32, and 33.

FIG. 34 is a cross-sectional view of a particular embodiment of amagnetic tunnel junction (MTJ) cell 3400. The MTJ cell 3400 includes anMTJ stack 3402 having a free layer 3404, a tunnel barrier layer 3106, afixed (pinned) layer 3108, and an anti-ferromagnetic (AF) layer 3426.The MTJ stack 3402 is coupled to a bit line 3410. Further, the MTJ stack3402 is coupled to a source line 3414 via a bottom electrode 3416 and aswitch 3418. A word line 3412 is coupled to a control terminal of theswitch 3418 to selectively activate the switch 3418 to allow a writecurrent 3424 to flow from the bit line 3410 to the source line 3414. Inthe embodiment shown, the fixed layer 3408 includes a magnetic domain3422 that has a fixed orientation. The free layer 3404 includes amagnetic domain 3420, which is programmable via the write current 3424.As shown, the write current 3410 is adapted to program the orientationof the magnetic domain 3420 at the free layer 3404 to a zero state(i.e., the magnetic domains 3420 and 3422 are oriented in the samedirection). To write a one value to the MTJ cell 3400, the write current3424 is reversed, causing the orientation of the magnetic domain 3420 atthe free layer 3404 to flip directions, such that the magnetic domain3420 extends in a direction opposite to that of the magnetic domain3422. In an illustrative embodiment, any of the embodiments depicted inFIGS. 2-33 may include an MTJ stack substantially similar to the MTJstack 3402.

FIG. 35 is a cross-sectional view of another particular embodiment of anMTJ cell 3500, which provides more fixed layer value and an increasedresistance. In particular, the MTJ cell 3500 includes an MTJ stack 3502including the free layer 3504, the tunnel barrier layer 3506, and thefixed layer 3508. The free layer 3504 of the MTJ stack is coupled to thetop electrode 3510 via a buffer layer 3530. In this example, the fixedlayer 3508 of the MTJ stack 3502 is coupled to the bottom electrode 3516via an anti-ferromagnetic layer 3538. Additionally, the fixed layer 3508includes a first pinned (fixed) layer 3532, a buffer layer 3534, and asecond pinned (fixed) layer 3536. The first and second pinned layers3532 and 3536 have respective magnetic domains which are oriented inopposing directions, thereby increasing fixed layer value and an overallresistance of the MTJ stack 3502. In a particular embodiment, such anincreased fixed layer value can enhance a read margin associated withthe MTJ stack 3502.

FIG. 36 is a cross-sectional view of an MTJ cell 3600 having a singleswitch device to access a single stored value. The MTJ cell 3600includes a bottom electrode including a first sidewall 3606, a bottomwall 3604, and a second sidewall 3608. The MTJ cell 3600 also includes acenter electrode 3610 and an MTJ stack 3612. The MTJ stack 3612separates the center electrode 3610 from the first sidewall 3606, thesecond sidewall 3608, and the bottom wall 3604 of the bottom electrode.In this embodiment, the MTJ stack 3612 includes a first magnetic domain3614 and a second magnetic domain 3616. The center electrode 3610 iscoupled to a bit line 3618. The first sidewall 3606 and the secondsidewall 3608 are coupled to a node 3624 via lines 3620 and 3622. TheMTJ cell 3600 also includes a switch 3626 having a first terminalcoupled to the node 3624, a second terminal 3630 coupled to a sourceline, and a control terminal coupled to a word line 3628.

FIG. 37 is a cross-sectional diagram of an MTJ cell 3700 having twoswitch devices to access two stored values. The MTJ cell 3700 includes abottom electrode including a first sidewall 3706, a bottom wall 3704,and a second sidewall 3708. The MTJ cell 3700 also includes a centerelectrode 3710 and an MTJ stack 3712. The MTJ stack 3712 separates thecenter electrode 3710 from the first sidewall 3706, the second sidewall3708, and the bottom wall 3704 of the bottom electrode. In thisembodiment, the MTJ stack 3712 includes a first magnetic domain 3714 anda second magnetic domain 3716. The center electrode 3710 is coupled to abit line 3718. The MTJ cell 3700 includes a first switch 3722 includinga first terminal 3720 that is coupled to the first sidewall 3706, acontrol terminal coupled to a node 3724, and a second terminal coupledto a first source line 3728. The MTJ cell 3700 also includes a word line3726 that is coupled to the node 3724. The MTJ cell 3700 furtherincludes a second switch 3732 that has a third terminal 3730 coupled tothe second sidewall 3708, a control terminal coupled to the node 3724,and a fourth terminal coupled to a second source line 3734. Althoughdepicted as having a shared word line 3726 and separate source lines3728 and 3734, in other embodiments separate word lines and a sharedsource line may instead be used.

In a particular embodiment, the first source line 3728 and the secondsource line 3734 may be selectively activated to read and/or write datafrom and to the first and second magnetic domains 3714 and 3716. In aparticular embodiment, a current or voltage is applied to the bit line3718 and is applied to the word line 3726 to activate the first andsecond switches 3722 and 3732. The first source line 3728, separatelyfrom and independent of the second source line 3734, may be activated toread data represented by the first magnetic domain 3714. In anotherparticular embodiment, the first source line 3728 and the second sourceline 3734 may be activated to read data represented by the first andsecond magnetic domains 3714 and 3716.

FIG. 38 is a cross-sectional diagram of an MTJ cell 3800 having threeswitch devices to access three stored values. The MTJ cell 3800 includesa bottom electrode including a first sidewall 3806, a bottom wall 3804,and a second sidewall 3808. The MTJ cell 3800 also includes a centerelectrode 3810 and an MTJ stack 3812. The MTJ stack 3812 separates thecenter electrode 3810 from the first sidewall 3806, the second sidewall3808, and the bottom wall 3804 of the bottom electrode. In thisembodiment, the MTJ stack 3812 includes a first magnetic domain 3814, asecond magnetic domain 3816, and a third magnetic domain 3817. Thecenter electrode 3810 is coupled to a bit line 3818. The MTJ cell 3800includes a first switch 3822 including a first terminal 3820 that iscoupled to the first sidewall 3806, a control terminal coupled to a node3824, and a second terminal coupled to a first source line 3828. The MTJcell 3800 also includes a word line 3826 that is coupled to the node3824. The MTJ cell 3800 further includes a second switch 3832 that has athird terminal 3830 coupled to the bottom wall 3804, a control terminalcoupled to the node 3824, and a fourth terminal coupled to a secondsource line 3834. The MTJ cell 3800 also includes a third switch 3838having a fifth terminal 3836 coupled to the second sidewall 3816, acontrol terminal coupled to the node 3824, and a sixth terminal coupledto the third source line 3840.

In a particular embodiment, the first source line 3828, the secondsource line 3834 and the third source line 3840 may be selectivelyactivated to read and/or write data from and to the first, third, andsecond magnetic domains 3814, 3817, and 3816. In a particularembodiment, a current or voltage is applied to the bit line 3818 and isapplied to the word line 3826 to activate the first, second, and thirdswitches 3822, 3832 and 3838. The first source line 3828, the secondsource line 3832, or the third source line 3840 may be separate andindependent of each other and may be activated to read data representedby the first, second, or third magnetic domain 3814, 3816, or 3817. Inanother particular embodiment, the first source line 3828, the secondsource line 3832, and the third source line 3840 may be activated toread data represented by the first, third, and second magnetic domains3814, 3817, and 3816. In an alternative embodiment, a third lateralelectrode (not shown) is proximate to a third sidewall that includes afourth magnetic domain (not shown), and the terminal 3830 is coupled tothe third lateral electrode and not to the bottom wall, to enableoperation of the MTJ cell 3800 using three lateral electrodeconnections.

FIGS. 39-40 are flow diagrams of a particular illustrative embodiment ofa method of forming a magnetic tunnel junction (MTJ) structure havingmultiple lateral magnetic domains. At 3902, a cap film layer isdeposited. Continuing to 3904, if there is a bottom via, the methodadvances to 3906 and a photo-etch and photo resist strip, via fill, andChemical-Mechanical Polishing process are applied to define a bottomvia. The method proceeds to 3908 and an inter-layer dielectric layer(IDL) and a cap film layer are deposited.

Returning to 3904, if there is no bottom via, the method proceeds to3908 and an inter-layer dielectric layer (IDL) and a cap film layer aredeposited. Moving to 3910, a lateral electrode trench is formed using aphoto-etch process, stopping at a bottom cap film layer. Continuing to3912, a lateral electrode is deposited and a reverse photo-etch-photoresist strip and chemical-mechanical polishing process is performed,stopping at a cap film layer. Proceeding to 3914, if a MTJ photo-etchwill be performed, the method advances to 3916 and a cap film layer isdeposited for an MTJ etching process. Continuing to 3918, a photo-etchand photo resist strip process is performed to define an MTJ trench.

Returning to 3914, if a MTJ photo-etch process will not be performed,the method proceeds to 3918 and a photo-etch and photo resist stripprocess is performed to define an MTJ trench. Continuing to 3920,multiple MTJ films are deposited including a first magnetic film layer,a tunnel barrier, and a second magnetic film layer. Moving to 3922, atop electrode is deposited on the second magnetic film layer. The methodadvances to 3924 and is continued in FIG. 40.

In FIG. 40, at 3924, the method continues to 4026 and a MTJ hardmask isdeposited, an MTJ photo-etching or reverse trench photo-etching processis performed, stopping at the cap film, and the photo-resist layer isstripped. Moving to 4028, if a reverse photo-etching process wasperformed, the method continues to 4030 and a chemical-mechanicalpolishing operation is performed on the MTJ structure and stopped at thecap layer. Proceeding to 4032, a sidewall photo-etch and photo resiststrip operation is performed to remove a sidewall of the MTJ stack.

Returning to 4028, if reverse trench photo-etching is not performed, themethod advances to 1032 and a sidewall photo-etch and photo resist stripoperation is performed to remove a sidewall of the MTJ stack. Continuingto 4034, if reverse trench photo-etching is performed, the method movesto 4036 and a cap film layer is deposited over the MTJ stack. Proceedingto 4038, an inter-layer dielectric layer is deposited and achemical-mechanical polishing process is performed. Returning to 4034,if reverse trench photo-etching is not performed, the method continuesto 4038 and an inter-layer dielectric layer is deposited and achemical-mechanical polishing process is performed. At 4040, athree-dimensional magnetic annealing process is performed. In aparticular example, where the MTJ structure is formed within a shallowtrench, the magnetic anneal may be performed in a horizontal X-Ydirection, to establish a horizontal magnetic orientation. In anotherparticular example, where the MTJ structure is formed within a deepertrench, the magnetic anneal may be performed in a horizontal x-directionand a vertical z-direction. Moving to 4042, a via photo-etch, photoresist strip, fill, and chemical-mechanical polishing (CMP) process isperformed. Advancing to 4044, a metal pattern is defined by trenching,photo-etching, plating, and chemical-mechanical processing processes orby a depositing and photo-etching process. The method terminates at4046.

In a particular embodiment, the method illustrated by FIGS. 39 and 40illustrate a process flow for the MTJ structures of FIGS. 2-13, whichmay be formed using an MTJ chemical-mechanical polishing process.Alternatively, the method illustrated by FIGS. 39 and 40 illustrate aprocess flow for the MTJ structures of FIGS. 14-25, which may be formedby an MTJ etching process. In a particular illustrative embodiment,trench depth and lateral electrode shape may be tightly controlled. In aparticular example, the tunnel barrier may be formed from MagnesiumOxide (MgO) or Aluminum Oxide (Al₂O₃). In a particular example, the topelectrode thickness may be controlled to fill a narrow trend gap withouta seam. The cap film layer may be formed from Silicon Nitride (SiN),Silicon Carbon (SiC) or other material, and the MTJ Chemical-MechanicalPolishing (CMP) process stops at the cap film layer. In a particularexample, a magnetic anneal process is applied in three dimensions toinitialize all horizontal and vertical magnetic domains in an annealfield direction.

FIG. 41 is a flow diagram of a second particular illustrative embodimentof a method of forming a magnetic tunnel junction (MTJ) structure havingmultiple lateral magnetic domains. At 4102, a trench is formed in asubstrate. In a particular embodiment, the surface of the substrate issubstantially planar. Continuing to 4104, a conductive terminal isdeposited within the trench. In a particular embodiment, depositing theconductive terminal includes forming a first conductive terminal withinthe trench to form a first lateral electrode and forming a secondconductive terminal within the trench to form a second lateralelectrode. The first conductive terminal is electrically isolated fromthe second conductive terminal. Proceeding to 4106, a magnetic tunneljunction (MTJ) structure is deposited within the trench. The MTJstructure includes a fixed magnetic layer having a fixed magneticorientation, a tunnel junction layer, and a free magnetic layer having aconfigurable magnetic orientation. The fixed magnetic layer is coupledto the conductive terminal along an interface that extends substantiallynormal to a surface of the substrate. The free magnetic layer isadjacent to the conductive terminal and carries a magnetic domainadapted to store a digital value. The method terminates at 4108. Itshould be clearly understood that additional fabrication processes maybe performed, and that each element of the method may be performed usingtechniques that are now known or that may be later developed. Forexample, in an illustrative embodiment, a cap layer may be deposited onthe substrate prior to forming the trench, the trench may be formedprior to depositing the conductive terminal, a chemical-mechanicalpolishing (CMP) process may be performed after depositing the conductiveterminal in the trench, the first and second lateral electrode may beformed by depositing a conductive film and then separating the lateralelectrodes, a reverse trench photo-etching process and CMP or MTJphoto-etching process may be performed after depositing the MTJstructure within the trench, a three-dimensional magnetic annealingprocess may be performed, other processing techniques may be performed,or any combination thereof.

In a particular embodiment, the MTJ structure includes ananti-ferromagnetic (AF) layer adjacent to the fixed magnetic layer, andthe fixed magnetic layer is coupled to the conductive terminal via theAF layer. The fixed magnetic layer may include a first portion coupledto the first conductive terminal along a first interface that extendssubstantially normal to a surface of the substrate and includes a secondportion coupled to the second conductive terminal along a secondinterface that extends substantially normal to the surface of thesubstrate. For example, the first portion may be coupled to the firstlateral electrode via the AF layer, and the second portion may becoupled to the second lateral electrode via the AF layer. In anotherparticular embodiment, the fixed magnetic layer further includes abottom portion that extends substantially parallel to the surface of thesubstrate.

In a particular embodiment, a photo-etching process may also beperformed to remove a portion of the inter-layer dielectric layeraccording to a pattern to form a cavity, and depositing the conductiveterminal includes depositing the conductive terminal within the cavity.For example, a lateral electrode may be formed within such a cavity. Ina particular embodiment, the method also includes depositing a secondconductive terminal of the structure. As an illustrative example, thesecond conductive terminal may include a top electrode. The secondconductive terminal may be electrically isolated from the firstconductive terminal.

In another particular embodiment, the tunnel junction barrier includes afirst junction portion that contacts the first portion of the fixedmagnetic layer along a third interface that extends substantially normalto the surface of the substrate. The tunnel junction barrier furtherincludes a second junction portion that contacts the second portion ofthe fixed magnetic layer along a fourth interface that extendssubstantially normal to the surface of the substrate. In a particularembodiment, a free magnetic layer is deposited within the trench. Thefree magnetic layer includes a first free portion that contacts thefirst junction portion along a fifth interface that extendssubstantially normal to the surface of the substrate and includes asecond free portion that contacts the second junction portion along asixth interface that extends substantially normal to the surface of thesubstrate.

FIG. 42 is a flow diagram of a third particular illustrative embodimentof a method of forming a magnetic tunnel junction (MTJ) structure havingmultiple lateral magnetic domains. At 4202, a trench is formed in asubstrate. The trench includes a first sidewall, a second sidewall, athird sidewall, a fourth sidewall, and a bottom wall. Continuing to4204, a first conductive terminal is deposited within the trenchproximate to the first sidewall and a second conductive terminal isdeposited within the trench. Proceeding to 4206, a magnetic tunneljunction (MTJ) structure is deposited within the trench. The MTJstructure includes a fixed magnetic layer having a magnetic field with afixed magnetic orientation, a tunnel junction layer, and a free magneticlayer having a magnetic field with a configurable magnetic orientation.The MTJ structure is adjacent to the first, the second, the third, andthe fourth sidewalls at respective first, second, third, and fourthlateral interfaces and adjacent to the bottom wall at a bottominterface. The free magnetic layer adjacent to the first conductiveterminal is adapted to carry a first magnetic domain to store a firstdigital value and the free magnetic layer adjacent to the secondconductive terminal is adapted to carry a second magnetic domain tostore a second digital value.

In a particular embodiment, the first, second, third and fourth lateralinterfaces extend approximately perpendicular to a surface of thesubstrate. In another particular embodiment, a third conductive terminalis formed proximate to the third sidewall of the trench. In a particularembodiment, a portion of the MTJ structure that is adjacent to thefourth sidewall is selectively removed to create an opening such thatthe MTJ structure is substantially u-shaped. An inter-layer dielectricmaterial may be deposited into the opening. In a particular embodiment,the portion of the MTJ structure may be selectively removed byperforming a photo-etching process to define a pattern on the MTJstructure and by removing the portion of the MTJ structure according tothe pattern. It should be clearly understood that additional fabricationprocesses may be performed, and that each element of the method may beperformed using techniques that are now known or that may be laterdeveloped. For example, in an illustrative embodiment, a cap layer maybe deposited on the substrate prior to forming the trench, the trenchmay be formed prior to depositing the first conductive terminal, achemical-mechanical polishing (CMP) process may be performed afterdepositing the first and second conductive terminal in the trench, areverse trench photo-etching process and CMP or MTJ photo-etchingprocess may be performed after depositing the MTJ structure within thetrench, a three-dimensional magnetic annealing process may be performed,other processing techniques may be performed, or any combinationthereof.

FIG. 43 is a block diagram of a wireless communication device 4300. Thewireless communications device 4300 includes a memory having an array ofMTJ cells 4332 and a magneto-resistive random access memory (MRAM)including an array of MTJ cells 4362, which are coupled to a processor,such as a digital signal processor (DSP) 4310. The communications device4300 also includes a cache memory device of MTJ cells 4364 that iscoupled to the DSP 4310. The cache memory device of MTJ cells 4364, thememory array of MTJ cells 4332 and the MRAM device including multipleMTJ cells 4362 may include MTJ cells formed according to a process, asdescribed with respect to FIGS. 2-42. In a particular embodiment, thecache memory of MTJ cell 4364, the memory array of MTJ cells 4332, andthe MRAM device including multiple MTJ cells 4362 provide a high datastorage density relative to conventional memory devices.

FIG. 43 also shows a display controller 4326 that is coupled to thedigital signal processor 4310 and to a display 4328. A coder/decoder(CODEC) 4334 can also be coupled to the digital signal processor 4310. Aspeaker 4336 and a microphone 4338 can be coupled to the CODEC 4334.

FIG. 43 also indicates that a wireless controller 4340 can be coupled tothe digital signal processor 4310 and to a wireless antenna 4342. In aparticular embodiment, an input device 4330 and a power supply 4344 arecoupled to the on-chip system 4322. Moreover, in a particularembodiment, as illustrated in FIG. 43, the display 4328, the inputdevice 4330, the speaker 4336, the microphone 4338, the wireless antenna4342, and the power supply 4344 are external to the on-chip system 4322.However, each can be coupled to a component of the on-chip system 4322,such as an interface or a controller.

Those of skill would further appreciate that the various illustrativelogical blocks, configurations, modules, circuits, and algorithm stepsdescribed in connection with the embodiments disclosed herein may beimplemented as electronic hardware, computer software executable by aprocessor, or combinations of both. Various illustrative components,blocks, configurations, modules, circuits, and steps have been describedabove generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure.

The steps of a method or algorithm described in connection with theembodiments disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module may reside in RAM memory, flash memory, ROM memory,PROM memory, EPROM memory, EEPROM memory, registers, hard disk, aremovable disk, a CD-ROM, or any other form of storage medium known inthe art. An exemplary storage medium is coupled to the processor suchthat the processor can read information from, and write information to,the storage medium. In the alternative, the storage medium may beintegral to the processor. The processor and the storage medium mayreside in an ASIC. The ASIC may reside in a computing device or a userterminal. In the alternative, the processor and the storage medium mayreside as discrete components in a computing device or user terminal.

The previous description of the disclosed embodiments is provided toenable any person skilled in the art to make or use the disclosedembodiments. Various modifications to these embodiments will be readilyapparent to those skilled in the art, and the generic principles definedherein may be applied to other embodiments without departing from thespirit or scope of the disclosure. Thus, the present disclosure is notintended to be limited to the embodiments shown herein but is to beaccorded the widest scope possible consistent with the principles andnovel features as defined by the following claims.

What is claimed is:
 1. A method of forming a magnetic tunnel junctiondevice,the method comprising: forming a trench in a substrate, thetrench including a plurality of sidewalls and a bottom wall; depositinga first conductive material within the trench proximate to one of theplurality of sidewalls and depositing a second conductive materialwithin the trench; depositing material to form a magnetic tunneljunction (MTJ) structure within the trench, the MTJ structure includinga fixed magnetic layer having a magnetic field with a fixed magneticorientation, a tunnel junction layer, and a free magnetic layer having amagnetic field with a configurable magnetic orientation; and selectivelyremoving a portion of the MTJ structure to create an opening in the MTJstructure.
 2. The method of claim 1, wherein the free magnetic layerincludes a first portion adapted to carry a first magnetic domain tostore a first digital value, and wherein the free magnetic layerincludes a second portion adapted to carry a second magnetic domain tostore a second digital value.
 3. The method of claim 1, wherein thefirst conductive material forms a first lateral electrode, and whereinthe second conductive material forms a second lateral electrode.
 4. Themethod of claim 1, wherein selectively removing the portion of the MTJstructure comprises performing a photo-etching process to define apattern on the MTJ structure and to remove the portion of the MTJstructure according to the pattern.
 5. The method of claim 1, whereinthe MTJ structure is adjacent to the plurality of sidewalls at aplurality of lateral interfaces, and wherein the MTJ structure isadjacent to the bottom wall at a bottom interface.
 6. The method ofclaim 5, wherein each of the plurality of lateral interfaces extendsapproximately perpendicular to a surface of the substrate.
 7. The methodof claim 1, wherein the first conductive material forms a firstconductive terminal, wherein the second conductive material forms asecond conductive terminal, and wherein the fixed magnetic layerincludes a first portion coupled to the first conductive terminal alonga first interface that extends substantially normal to a surface of thesubstrate and a second portion coupled to the second conductive terminalalong a second interface that extends substantially normal to thesurface of the substrate.
 8. The method of claim 1, wherein the freemagnetic layer includes a bottom portion adjacent to a bottom electrode,the bottom portion adapted to carry a magnetic domain.
 9. The method ofclaim 1, further comprising depositing a third conductive materialwithin the trench.
 10. The method of claim 1, further comprisingdepositing an inter-layer dielectric material into the opening.
 11. Asystem comprising: means for forming a trench in a substrate, the trenchincluding a first sidewall, a second sidewall, a third sidewall, afourth sidewall, and a bottom wall; means for depositing a firstconductive material within the trench proximate to the first sidewalland depositing a second conductive material within the trench; means fordepositing material to form a magnetic tunnel junction (MTJ) structurewithin the trench, the MTJ structure including a fixed magnetic layerhaving a magnetic field with a fixed magnetic orientation, a tunneljunction layer, and a free magnetic layer having a magnetic field with aconfigurable magnetic orientation; and means for selectively removing aportion of the MTJ structure that is adjacent to the fourth sidewall tocreate an opening such that the MTJ structure is substantially u-shaped.12. the system of claim 11, wherein the free magnetic layer includes afirst portion adapted to carry a first magnetic domain to store a firstdigital value, and wherein the free magnetic layer includes a secondportion adapted to carry a second magnetic domain to store a seconddigital value.
 13. The system of claim 11, wherein the first conductivematerial forms a first lateral electrode, and wherein the secondconductive material forms a second lateral electrode.
 14. The system ofclaim 11, wherein the means for selectively removing the portion of theMTJ structure comprises means for performing a photo-etching process todefine a pattern on the MTJ structure and to remove the portion of theMTJ structure according to the pattern.
 15. The system of claim 11,wherein the MTJ structure is adjacent to the first, the second, thethird, and the fourth sidewalls at respective first, second, third, andfourth lateral interfaces, and wherein the MTJ structure is adjacent tothe bottom wall at a bottom interface.
 16. The system of claim 15,wherein the first, second, third and fourth lateral interfaces extendapproximately perpendicular to a surface of the substrate.
 17. Thesystem of claim 15, wherein the bottom interface extends approximatelyparallel to a surface of the substrate.
 18. The system of claim 11,wherein the first conductive material forms a first conductive terminal,wherein the second conductive material forms a second conductiveterminal, and wherein the fixed magnetic layer includes a first portioncoupled to the first conductive terminal along a first interface thatextends substantially normal to a surface of the substrate and a secondportion coupled to the second conductive terminal along a secondinterface that extends substantially normal to the surface of thesubstrate.
 19. The system of claim 11, wherein the free magnetic layerincludes a bottom portion adjacent to a bottom electrode, the bottomportion adapted to carry a magnetic domain.
 20. The system of claim 11,further comprising means for depositing an inter-layer dielectricmaterial into the opening.